Combustion turbines generally take in air and compress the air in a compression turbine stage. Gas or oil fuel is metered into a combustion chamber and the resulting hot exhaust gas then passes over the turbine blades creating torque on a shaft. Typically the shaft is connected to a generator that then produces electricity. The metering of the fuel in the combustion chamber controls the speed of the turbine as the load varies
U.S. Pat. No. 7,044,434, issued May 16, 2006, and entitled “High Recovery Sonic Gas Valve,” is directed to a gas valve design in which the inlet flow enters the valve transverse or orthogonal to the outlet flow. The gas control valve controls the flow of gas, including air and/or fuel, for an industrial or gas turbine or other flow control system. The valve is described as providing sonic flow through the nozzle throat per pressure ratios (P1/P2) at or above approximately 1.04. The valve is disclosed as having a valve body with a gas inlet, a gas outlet and a nozzle throat for a valve needle. The valve needle has a contoured surface that is shaped to provide a desired gas flow versus actuator piston stroke and the valve nozzle has a converging flow where the flow path cross-sectional area is reducing along the direction of flow. The entire contents of U.S. Pat. No. 7,044,434 are incorporated herein by reference.
U.S. Pat. No. 7,137,612, issued Nov. 21, 2006, and entitled “High Recovery Metering Valve,” is directed to a metering valve having an inlet, an outlet, and a plenum. A valve poppet is moveably positioned within the internal valve trim and the valve poppet includes a distal portion that is tapered. The inlet and the outlet of the valve are orientated about ninety degrees with respect to each other. The valve is described as providing improved pressure recovery. The entire contents of U.S. Pat. No. 7,137,612 are incorporated herein by reference.